Human-animal interactions have been studied for decades, characterizing the quality of such interactions and the effect they have on psychological functioning such as self-esteem and how people deal with grief. This work has extended to childhood, showing that many of the beneficial effects of relationships with companion animals observed with adults are also true in children. However, little is known about infants' relationships and interactions with animals, and how such experiences contribute to development. It is unknown, for example, how parents encourage or shield infants from interactions with companion animals, and whether interactions with animals contributes to infants' rapidly developing mental functioning. Therefore, a complete understanding of human-animal interactions, and how such interactions influence development, requires characterizing infants' experiences with companion animals. Characterizing infants' interactions and relationships with animals is also important because infant development is shaped by their experience-they learn the language they hear, the kind of faces they look at, and to interact with the kinds of objects in their environment. Moreover, differences in experience can have a profound effect on healthy development. Children who are raised in institutions, in poverty, or without a caring attentive caregiver have different developmental outcomes than children who are raised under other conditions. One common difference between children is the presence of pets in the home. Examining variations in infants' experience with pets, and how those variations contribute to their developing cognitions about animals, provides a model for systematically studying environmental influences on infant development as well as provides much needed information about the quality and quantity of infants' experience with companion animals. Although infants' perception of and learning about animal stimuli has been studied for decades, there has been little attempt to relate this learning to their experience with pets in the home. These previous studies have provided significant understanding into infants' basic perception of animals, revealing that by 3 to 4 months infants have sophisticated abilities to discriminate between, remember, categorize a wide variety of animals. Recently, infants' experience with pets in the home has been recognized as a potential contributor to this early development. This project will provide detailed information characterizing the quality and quantity of infants' interactions with animals through interviews with parents (Experiment 1), parental responses to questionnaires (Experiment 2), and observations in the home (Experiment 3). The effect of differences in infants' interactions will be examined by evaluating how infants with different experiences visually scan naturalistic scenes of infants in everyday activities in the presence of animals (Experiment 4). The results of these experiments will add to our understanding of human-animal interactions across the lifespan and begin to uncover the ways in which relationships with companion animals contributes to infants' development.